The present invention relates to arrangements for switching electromagnetic loads in general, and more particularly to an arrangement for rapid switching of electromagnetic loads usable especially in the fuel delivery and metering, electromagnetically operated, valves of a fuel injection device of an internal combustion engine.
There are already known various constructions of switching arrangements of this type. Such switching arrangements include at least a series arrangement of the electromagnetic load with a switching transistor and a measuring resistor. For the reliable operation of such a switching arrangement, it is, for example, necessary to arrange a relief diode, which may be so arranged that it can be switched on and off, in parallel to the electromagentic load. It is also known to influence the switching transistor and, in certain instances, the transistor which controls the relief diode, at least in dependence on the voltage applied to the measuring resistor.
However, the known arrangements of this type have the disadvantage that the switching-on and switching-off times of the electromagnetic load are relatively long. Additional disadvantages of such arrangements are that relatively high energy losses temporarily occur in the switching arrangement, as well as that the arrangements of this type can only under certain limited conditions be used for the construction of a timing control circuit.